1. Field of Invention
The present invention relates to a semiconductor process. More particularly, the present invention relates to a method for cleaning polymer residues on a wafer.
2. Description of Related Art
In the semiconductor process, the patterning process of a material layer usually includes a photolithography process for forming a patterned photoresist layer and an etching process with the use of the patterned photoresist layer as an etching mask. Since the photoresist layer is made of organic material, the etching residue often remains on the substrate so as to induce a lot of process problems. In the damascene process, especially for the metal hard mask layer used as the etching mask, the etching residue, which seriously affects the later performed process, remains on the sidewall of the damascene opening after the etching process is performed. In the later performed semiconductor process, if the etching residue is not properly removed, the residue will affect the later performed process steps and further decrease the quality of the metal interconnects.
In order to solve the problem of leaving the etching residue on the substrate, in the conventional manufacturing process, a wet clean process is performed with the use of the surfactant to remove the etching residue from the substrate. However, as to the process for forming the damascene opening with the use of the metal hard mask layer, it is hard to clean out the etching residue remaining on the sidewall of the damascene opening formed on the substrate. Hence, the quality of the metal interconnects is dramatically affected and the yield is decreased as wall.